Photoelectric switch adapter



p 2 1962 G. w. BERNHEIM 3,056,035

PHOTOELECTRIC SWITCH ADAPTER Filed March 15, 1961 2 Sheets-Sheet 1 48 49 Fl I.

U INVENTOR "6 GEORGE w. BERNHEIM f BY 1; FIG. IO. Q a. 6M

ATTORNEY.

Sept. 25, 1962 G. W. BERNHEIM PHOTOELECTRIC SWITCH ADAPTER Filed March 15, 1961 2 Sheets-Sheet 2 23 FIG. 5.

a2 122 75 76 I 96 30i INVENTOR GEORGE W. BERNHEIM BY AT TORN E Y;

United States Patent Ofiiice 3,056,035 Patented Sept. 25, 1962 3,056,035 PHOTOELECTRIC SWITCH ADAPTER George W. Bernheim, Bronx, N.Y. Vericontrol Associates, 72 Main St., Yonkers, N.Y.) Filed Mar. 13, 1961, Ser. No. 95,334 9 Claims. (Cl. 250-239) This invention relates to the art of photoelectric switches and particularly concerns a photoelectric switch adapter for an electric lamp, lantern, luminaire, or other electrical appliance.

Heretofore, it has been known to employ photoelectric switches in association with lamp posts, lanterns, and other electrical appliances, to turn the appliances on automatically when ambient daylight decreases at dusk and to turn the appliances off automatically at dawn. Such switches have been housed in special canopies or boxes which were wired to the lamp posts, lamp fixtures or appliances. The necessity of wiring the switch to an existing lamp post or fixture required drilling of holes in a post or casing to pass wires therethrough, and to anchor bolts or screws. This was objectionable. The disposition of a photoelectric switch in an outside position on a post or fixture exposed to the weather was undesirable, and required frequent servicing to maintain the switch in an operative condition. Also supplementary brackets, collars and fittings were required to effect installations.

The present invention is directed at overcoming the above and other difiiculties and disadvantages by provid ing a photoelectric switch housed in an adapter which can be disposed with a lantern globe or appliance housing, the adapter having a plug to screw into a power supply receptacle and having a socket or recess to receive a lamp bulb or other appliance.

A further object is to provide a photoelectric switch adapter which can be connected into a power supply and load circuit solely by screw connections Without requiring any supplementary wiring or any other supplementary fixture or adapter.

Another object is to provide a photoelectric switch adapter including a housing for the switch rotatable with respect to a screw plug mounting so that a photoelectric element in the housing can be oriented in an optimum position for exposure to ambient light.

Still another object is to provide a ventilated photoelectric switch adapter of the character described having a light filter which is substantially opaque to undesired radiation and transparent to ambient daylight, so that only ambient light reaches the photoelectric cell.

Another object is to provide an adapter of the character described with a heat sink to conduct and radiate heat away from the photoelectric cell.

The invention can employ any type of photoelectric cell but is especially intended for use with a photoconductive type of photoelectric cell which changes internal resistance depending on the intensity of light impinging thereon. Such cells are very responsive and sensitive to incident light which is a desirable characteristic. However photoconductive cells have the characteristic of changing response parameters adversely when subjected to high ambient heat. The photoconductive cells have sensitive crystalline elements which frequently lose all activity or sensitivity when externally heated. The present invention precludes loss of sensitivity by provision of an optical filter substantially opaque to heat rays, of a heat sink member or assembly, a novel ventilation means, and by other characteristics of the invention to be described. When the invention employs a thermal relay which radiates heat in the adapter, the novel ventilation system and heat sink protect the photoelectric cell from this source of heat. The ventilation system also serves to cool the relay preventing it from overheating. The invention will be described in connection with a lantern which is exemplary of only one appliance in which the adapter can be used.

The invention will be best understood from the following detailed description, taken together with the drawing wherein:

FIG. 1 is a vertical sectional view through part of a lantern showing in elevation a photoelectric adapter device embodying the invention, mounted in the lantern.

FIG. 2 is a perspective view of the adapter on a reduced scale.

FIG. 3 is a top plan view of the adapter.

FIG. 4 is a bottom plan view of the adapter.

FIG. 5 is a sectional view on an enlarged scale taken on line 55 of FIG. 3.

FIG. 6 is a cross sectional view taken on line 6-6 of FIG. 5.

FIG. 7 is a cross sectional view taken on line 7-7 FIG. 5 with parts shown in bottom plan view.

FIG. 8 is a perspective view of a heat sink bar or plate employed in the device to conduct and radiate heat away from the photoelectric cell.

FIG. 9 is a top plan view of a flange plate employed in the device.

FIG. 10 is a sectional view taken on line 10*10 of FIG. 9.

FIG. 11 is a side elevational view of the taken on line 11-11 of FIG. 10.

FIG. 12 is a circuit diagram of the device.

Referring first to FIGS. 1-7, there is shown the device 20 embodying the invention. The device includes a generally cylindrical housing or casing 22 having a flat top 24 from which extends a tubular neck 26. In this neck is disposed a conductive threaded sleeve 23 which serves as a socket for an incandescent electric lamp 28 or other electrical .appliance. Spaced from the sleeve is a central contact element 30; see FIGS. 3 and 5. A series of holes 21 for ventilation are formed in top 24.

The casing 22 has an open bottom in which is detachably secured by screws 24 a bottom flange plate 25. Extending downwardly from and axially aligned with the flange plate is a rotatable plug 29. The plug has a threaded conductive sleeve 32 and a centrally disposed contact element 34 spaced from the sleeve 32. Ventilation holes or openings 33 .are formed in plate 25.

FIG. 1 shows that plug 29 can be screwed into a conventional receptacle or socket of a lantern 40. Power is supplied to the socket 35 by electric Wires 42. A tubular post 43 supports the lantern. Fitting 44 of the lantern screws on top of the post. The fitting has an annular flange 45 on which is supported transparent globe 46. The globe may have a metal dome 48 thereon. Holes 49 in the dome and holes 50 in the base of the fitting permit passage of air upwardly through the lantern as indicated by arrows A.

The lamp 28 has its threaded base screwed into the socket in neck 26 of the adapter 20. The plug 29 of the adapter is screwed into socket 35 as above mentioned. Projecting upwardly from the top 24 through a slot 47 is a metal plate or bar 49 which serves as a heat sink member to conduct ambient heat away from the photoelectric cell. Bar 49 may have slits forming fins or fingers 67 at its end. The fins 67 improve the heat radiation efliect of the bar 49.

In FIGS. 5 and 7 is shown the interior of the casing. A switch 70 mounted at the underside of top 24 by rivets 72 has a pushbutton 74. The pushbutton extends downwardly to contact the upper end of a screw 75 carried at one end of a bimetallic element 76 of a thermal relay 64. The other end of the bimetallic element '76 is secured to a spacer block 77 carried at the ends of two flange plate temperature compensating bimetallic elements 78. The other ends of the bimetallic elements are secured by rlvet 79 to bosses 81 in the interior of the housing. A re sistance heater 82 is mounted on element 76. The photoelectric cell 90 is a cylindrical member fitted in a cylindrical metal eyelet 92. The eyelet has an outer annular flange 94 which is juxtaposed to the rim of a hole 95 formed in the lower end 96 of bar 49; see FIG. 8. Opposed sernicylindrical recesses 97a, 98a, "99a and 97b, 98b, 99b are formed in respective abutting portions of the casing 22 and flange plate respectively. Recesses 97a, 97b define a cylindrical seat for the body of eyelet 92. Recesses 98a, 98b define a cylindrical seat for the flange 94 of the eyelet. Recesses 99a, 99b define a circular opening through which the cell 90 is exposed to the exterior of the casing; see also FIGS. 9ll. In hole 95 is seated an optical filter disk 38 which is substantially opaque to red rays and transparent to blue-green light rays. The filter disk 38 excludes heat rays emanating from the lamp or other appliance and reflected by the lantern globe 40 to the adapter. The filter disk attenuates to a very low level light rays of the lamp reflected by the lantern globe to the adapter so that such reflected light rays which are predominantly red and yellow have substantially no eifect on the photoelectric cell. Ambient light such as sky light and daylight which are predominantly blue-green are freely transmitted by the optical filter to the photoelectric cell 90. Thus the filter discriminates against local sources of light and heat rays in favor of ambient light rays.

In FIGS. 9-11 is shown to best advantage the structure of the flange plate 25. It will be noted that the plate has an annular portion 100 in which are the circumferentially spaced arcuate slots or openings '33 which serve as the lower ventilation passages for the device. These openings permit passage of air into the interior of the casing. Holes 104 in plate 25 receive screws 24 for securing the flange plate to the casing 22. The screws engage in threaded holes 31 formed in bosses 37 in the casing; see FIG. 7. Plate 25 has arcuate edges 25 which fit within depending arcuate ridges 106 at the underside of the casing; see FIGS. 4 and 5.

The flange plate 25 has an annular shoulder 108 formed with a central opening 110. The plug 29 extends through opening 110. The plug has an annular flange 112 formed with a circular groove 114; see FIGS. and 6. This groove extends about 340 of are, being interrupted by a radial stop element 115. This stop element serves as an obstruction to limit turning of the plug on shoulder 108. An upstanding projection 116 is formed on shoulder 108 as shown in FIGS. 9-11. This projection will be contacted by stop element 115 to prevent the casing and flange from turning on the plug through more than approximately 340". A recess 120 is formed in the flange plate between recesses 98b and 99b to seat the bottom of bar or plate 49.

Suitable electric wires interconect the switch 70, resistance heater 82, cell 90 and electrical contacts as shown schematically in FIG. 12. Lamp 28 is there shown schematically with its base contact 122, 124 engaged with socket contacts defined by sleeve 23 and central contact 30. Wire 125 connects the socket contact 30 with contacts 128 of switch 70. The screw 75 of bimetallic element 76 contacts the pushbutton 74 for opening the switch when the heater element 82 is energized. One terminal of cell 90 is connected to one terminal of the heater element. Wire 134 connects the other terminal of the cell 90 to wire 136. Wire 1136 is connected between socket contact 23 and plug sleeve contact 32. The other plug contact 34 is connected via wire 138 to the other switch contact 126 and other heater terminal. The terminals 140, 142 of the lantern receptacle 35 which engage the plug contacts 32, 34 are connected to the power supply PS.

To install the adapter 20, it is disposed axially vertical and its plug is screwed into the receptacle 35 of the lantern while the base of lamp 28 is screwed into the socket of the adapter. The casing 22 is then turned while plug 29 is stationary until the photoelectric cell is oriented geographically in an optimum position, preferably to the north. During the day, ambient light, preferably north light, arriving at the photoconductive photoelectric cell through filter disk 38 will lower the internal electrical resistance of the cell causing the heater 82 to be energized and the bimetallic element 76 will be heated to open switch 70. At dusk, the intensity of ambient light will fall and the resistance of the cell 90 will increase to cause heater 82 to become substantially deenergized. The bimetallic element will cool 011 and the pushbutton 74 will be released allowing the switch to assume its normally closed position. This closes the power supply circuit to lamp 28 which then remains lighted until dawn when the increasing ambient light lowers the resistance of the cell 90, thereby actuating and energizing heater 82. The bimetallic element 76 heats up and bends to open switch 70 and the lamp light is extinguished. This arrangement is fail safe since the switch 70 is normally closed and remains closed and lamp 28 remains lighted if for any reason the thermal relay 64 or photoelectric cell 90 should fail to operate.

Instead of a thermal relay, an electromagnetic relay may be used. Such a relay may be of miniature size, and can be inserted inside cavity 29 in plug 29. Switch 70 can then be placed at the bottom of casing 22 to shorten wires 136, 138. This arrangement will also permit reduction of the size of casing 22.

The filter 38 which is recessed in openings 99a, 99b effectively shields the cell 90 from unwanted light and heat rays. This is especially important because the photoconductive cell employs a sensitive crystalline element 91 which is adversely affected by heat. The metal eyelet 92 and cooperating bar or plate 49 serve as a heat sink assembly to shield the cell 90 from heat and to conduct the heat away from the cell. The fins or fingers 67 of bar 49 are located in the draft of air passing through the lantern globe which cools bar 49. A further draft of air is provided to ventilate the interior of the adapter 20. Air enters through arcuate holes 33 in the flange plate and leaves through the series of closely spaced holes 21 formed in the top of the housing near bar 49 as shown in FIGS. 2', 3 and 7. This internal draft of air cools eyelet 92 so that the heat sink assembly 49, 92 is externally and internally cooled by two air drafts.

The rotatable mounting of the adapter casing with respect to the lamp post is especially advantageous since it is always possible to rotate the adapter for optimum geographic positioning or orientation of the photoelectric cell.

It will be noted that the adapter makes it unnecessary for any wiring to be used in mounting it in the lantern. It screws into place easily and is inconspicuously located inside the lantern. It is protected by the transparent glass or plastic globe from the weather, wind and dust, yet the cell is exposed to ambient light for proper operation. The two drafts of air inside and outside the adapter keep it properly cooled for continuous, trouble-free functioning. All parts except electrically conductive ones may be made of plastic or other suitable insulation material. The several parts can be made on mass production machinery at low cost. The several parts are readily assembled and easily disassembled for servicing.

While the invention has been explained in connection with a lamp on a lamp post, it will be apparent that the adapter can be used with any lantern, light fixture, lamp of other design, or with any other type of electrical appliance which requires to be switched on and off at different ambient light levels.

What is claimed and sought to be protected by Letters Patent of the United States is:

1. A photoelectric switch adapter for an electrical appliance, comprising a generally cylindrical casing, said casing having an extension at one end defining a socket for receiving a power consuming load, said casing having an open other end, a flange plate closing said open other end of the casing, a plug carried by said flange plate axially aligned with said extension for mounting in a power supply receptacle, said plug being rotatable with respect to the flange plate and easing, said casing having a lateral opening therein, and a photoelectric cell exposed at said opening.

2. A photoelectric switch adapter for an electrical appliance, comprising a generally cylindrical casing, said casing having a cylindrical extension at one end defining a socket -for receiving a power consuming load, a plug carried at the other end of the casing and rotatable with respect to the casing, and a photoelectric cell exposed at a lateral opening in a side of the casing, opposite ends of the casing having vent holes therein to permit passage of a draft of air through the casing to ventilate the interior thereof.

3. A photoelectric switch adapter according to claim 2, further comprising a thermally conductive plate located adjacent to the cell at the vent holes for conducting heat from the cell.

4. A photoelectric switch adapter according to claim 2, further comprising a thermally conductive eyelet disposed in said lateral opening in the casing, said cell being seated inside said eyelet, and a thermally conductive plate juxtaposed to said eyelet for conducting heat away from the cell.

5. A photoelectric switch adapter according to claim 2, further comprising thermally conductive means supporting the photoelectric cell to conduct heat away from the cell, and an optical filter disposed adjacent to said cell at said opening to screen out locally generated light and heat rays while transmitting outside ambient light to the cell.

6. A photoelectric switch adapter according to claim 5, further comprising a switch in the casing, a bimetallic element disposed adjacent the switch to actuate the same,

said element having an associated heater to heat the ele-,

ment, said cell and heater being electrically connected in circuit with each other, and said switch, socket and plug having terminals electrically connected in circuit with each other, whereby said load is energized when said heater is deenergized and said load is deenergized when said heater is energized.

7. A photoelectric switch adapter for an appliance, comprising a generally cylindrical hollow casing, said casing having an extension at one end defining a socket :or receiving a power consuming load device, a plug carried by the casing at the other end thereof for insertion in a power supply receptacle, said plug and casing being mutually rotatable with respect to each other, stop means in the casing limiting rotation of the plug to less than 360, said casing having a lateral opening therein, an optical filter disposed in said opening, and a photoelectric cell disposed adjacent to said filter, whereby undesired locally generated light and heat rays are excluded from the cell while desired ambient light is transmitted to the cell.

8. A photoelectric switch adapter according to claim 7, further comprising a switch in the casing, and a relay adjacent to the switch to operate the same, said relay and cell being electrically connected in circuit with each other, whereby the relay opens the switch when the cell is illuminated by ambient light and the relay closes the switch when ambient illumination of the cell falls to a predetermined level.

9. A photoelectric switch adapter according to claim 7, further comprising a switch having normally closed contacts in circuit with terminals of said plug and socket, and a relay adjacent to the switch to operate the same, said relay and cell being electrically connected in circuit with each other, whereby the switch is held open by the relay and said load device is deenergized only while ambient light of predetermined wavelength and intensity is transmitted to the cell, and whereby said switch remains closed and said load device is energized at all other times.

References Cited in the file of this patent UNITED STATES PATENTS 1,838,329 Shapiro Dec. 29, 1931 2,631,247 Shaw Mar. 10, 1953 2,680,817 Haynes June 8, 1954 2,709,224 Garnick May 24, 1955 2,748,223 Frank May 29, 1956 2,967,981 Wise Jan. 10, 1961 2,978,591 Ringger Apr. 4, 1961 

